Loud speaker



Aug. 17 1926.

` lH. L. KENT LOUD SPEAKER 9 Filed may 17. 1924 huma, Ang. 17, 1926.

UNITED STATES HORACE L. KENT, 0F BROOKLYN, NEW YEK.

LOUD SPEAKER.

Appunti@ ma my 17, 1.924. 'serial in. cranes.

My invention relates to 'what ie sometimes termed a reproduoer or receiver. The main object is to provide n. simple and reliable mechanism for reproducing faithfully words and music so. that they can be heard at a distance land yet without the use of a horn.

In carrying out the invention I employ a large special diaphra in end sounding board l0 construction. The Liaphragm is operated in any suitable manner either electromngnetically or by' what is termed a phonof nph record. The preferred form is ilustrated in the accompanying drawing.

Fig.4 1 is a front view of parts embodying improvements of my invention on a small -sca e.

Fig. 2 is a sectional view of the same, full 'sized 3 is an enlarged fragmentary section showing the connection between the diaphragm and the operating member.

Fig. 4 is a section on line 4-1, Fig. 1. In the particular exemple shown the energizing coil 5 is supported at one pole of a' Vmagnet 6, 'which is supported by a bracket 7. The armature 8 is )ivoted tothe other pole of the magnet an adapted to be nd- )usted and vibrated in a manner common in telephone receivers.

The center of the diaphragm 9 is com nected to the armature 8 by a rod or wire 10. The outer1 edge or rim of the diaphragm is preferably" reinforced by a ring 11, which is supported preferably by the outer edge of the box 12. For convenience in mnnufnc ture. transportation and use., the box i3 prei erably provided with u bottom 13 to which the brackets 7 ure secured. The diaphragm should be quite large in diameter in order to produce the best results, for instance, eight inches in diameter or even larger.

The sleeve 14- and thc washer 15 are Secured to the diaphragm 9. The bushing 16 is screwed on to the end of the wire 10 and held in position by the clamp nut 17, and has un index pointer 1.8 extending from one edge. und movable over u scale or dial on the diaphragm. A. stop 19 limits the rotation of the pointer 18. The screw 20 serves to lock the bushing 1C in the Slcci'c i14e. When the armature is vibrntcd in the usuel manner it will transmit motion to the diaphragm i) through the Wire 1G, bushing 16, and sieevo 14C.

Immediately' hack of the din n sounding hoard 21 which. is preferably, supported outer edge of the box 12 either directly or ind ectiy. This sounding board 21 has reinforcing rim or ring'22 and the rings .l1 end 22 are scoured together by n series of screws l. have found that very satisfactory results caribe obtained by the use of a diephrugn'i made of bakelite or waterproof fibre approximately y of an inch thick, and a. soundin approximately 332 of en inch thick. The diaphragm und the Sounding board must be secured close together and properly adjusted with respect to each other to roduce the desired results, for instance, t ey may be spaced l@ of un inch apart. The spacing can be effected in any suitable manner, as for instance, by means of washers 24. When these Washers are of definite thickness, of course, very little adjustment is poseible, but by making the washers somewhat resilient it is possible tof-adjust the diaphragm and sounding board with respect to each other so as to obtain materiel` modification .in the volume and quality of reproduction. I may also, in some cases prefer to employ a post or sound transmitting niember 25 clamped between the diaphragm and the sounding board neur the center so as to couple the two members together and increase the volume of tone. i

Preferably there is an openingr around the major part of the periphery of the space between the diaphragm and the sounding board as shown et 26 in Fig. 4 through which the air vibrations may escupe and thus out through the screen 27 ut the top. The sides of the box may also have screened openings as at 28 if desired.

While I am not able to fully explain the theory of operation of this invention, experience has Shown that it is possible to obtain by it quite remarkable effects of clarity and smoothness of reproduction throughout the widest range of pitch und che ter of sound. Tones which becotn-.f bla t and unnatural when thrown 'from n horn are sounded clearly and naturally by the combined diaphragm and sounding board.

kI claim:

phragm 9 isx board of wood 10 Eroximateiy f5 l. Y loud speaker comprising e. disiphragm of upwards of 9 inches in diameter, a sounding board of approximately the same diametei, und ai seiies of washers inteiposefi 5 between the rims of said diaphragm and said sounding board, and menus he space 'between said members.

2. ioud speaker comprising :L diaphragm at least 8 inches in diameer and ap of an inch thick, a sounding Gard @E of an inch thick spaced, apprsxfor varying eter, :md means for vibrating said diaphsagm.

HORACE L. KENT. 

